Curved surface sensor pattern

Abstract

A touch sensor includes a flexible substrate, a plurality of sense electrodes and a plurality of drive electrodes disposed on the flexible substrate, a plurality of electrode branches, and a central spine. Each of the plurality of sense and drive electrodes includes electrode teeth, and electrode teeth of the sense electrodes are interdigitated with electrode teeth of the drive electrodes. Each particular electrode branch includes a portion of at least one of the drive electrodes and a portion of at least one of the sense electrodes. The central spine includes tracks that are coupled to the sense and drive electrodes. When the touch sensor is not formed into a three-dimensional shape, at least a portion of one of the electrode branches is separated from an adjacent electrode branch by a gap. When the touch sensor is formed into a three-dimensional shape, the gap is substantially eliminated, thereby forming a substantially continuous touch-sensitive surface.

What is claimed is: 
     
       1. A touch sensor comprising:
 a flexible substrate; 
 a plurality of sense electrodes and a plurality of drive electrodes disposed on the flexible substrate, each of the plurality of sense electrodes and the plurality of drive electrodes comprising a plurality of electrode teeth, wherein electrode teeth of the sense electrodes are interdigitated with electrode teeth of the drive electrodes; 
 a plurality of electrode branches, each particular electrode branch comprising a portion of at least one of the drive electrodes and a portion of at least one of the sense electrodes; and 
 a central spine comprising a plurality of tracks coupled to the plurality of sense and drive electrodes; 
 wherein:
 the plurality of electrode branches comprises:
 a plurality of first electrode branches located on a first side of the central spine; and 
 a plurality of second electrode branches located on a second side of the central spine that is opposite to the first side; 
 
 when the touch sensor is not formed into a three-dimensional shape, at least a portion of one of the electrode branches is separated from an adjacent electrode branch by a gap; and 
 when the touch sensor is formed into the three-dimensional shape, the gap is substantially eliminated, thereby forming a substantially continuous touch-sensitive surface. 
 
 
     
     
       2. The touch sensor of  claim 1 , wherein the flexible substrate comprises:
 polyimide; 
 polyethylene terephthalate (PET) with indium tin oxide (ITO); or 
 FR4. 
 
     
     
       3. The touch sensor of  claim 1 , wherein the plurality of drive and sense electrodes are formed on a single layer on the flexible substrate. 
     
     
       4. The touch sensor of  claim 3 , further comprising a coverlay disposed on top of the single layer. 
     
     
       5. The touch sensor of  claim 1 , wherein:
 the plurality of drive electrodes comprises a first drive electrode and a second drive electrode; 
 the first drive electrode is located in a particular one of the plurality of first electrode branches on the first side of the central spine; 
 the second drive electrode is located in a particular one of the plurality of second electrode branches on the second side of the central spine that is opposite to the first side; 
 the first drive electrode and the second drive electrode are adjacent to each other across the central spine and are both coupled to a common track of the central spine. 
 
     
     
       6. A touch sensor comprising:
 a flexible substrate; 
 a plurality of sense electrodes and a plurality of drive electrodes disposed on the flexible substrate, wherein a portion of each of the plurality of sense electrodes is interleaved with a least a portion of one of the plurality of drive electrodes; and 
 a plurality of electrode branches, each particular electrode branch comprising a portion of at least one of the drive electrodes and a portion of at least one of the sense electrodes; 
 wherein:
 the plurality of electrode branches comprises:
 a plurality of first electrode branches located on a first side of a central spine; and 
 a plurality of second electrode branches located on a second side of the central spine that is opposite to the first side; 
 
 when the touch sensor is not formed into a three-dimensional shape, at least a portion of one of the electrode branches is separated from an adjacent electrode branch by a gap; and 
 when the touch sensor is formed into the three-dimensional shape, the gap is substantially eliminated, thereby forming a substantially continuous touch-sensitive surface. 
 
 
     
     
       7. The touch sensor of  claim 6 , wherein the central spine comprises a plurality of tracks coupled to the plurality of sense and drive electrodes. 
     
     
       8. The touch sensor of  claim 7 , further comprising a connector coupled to the tracks of the central spine. 
     
     
       9. The touch sensor of  claim 6 , wherein
 the plurality of sense electrodes and the plurality of drive electrodes comprise electrode teeth; and 
 electrode teeth of the sense electrodes are interdigitated with electrode teeth of the drive electrodes. 
 
     
     
       10. The touch sensor of  claim 6 , wherein the flexible substrate comprises:
 polyimide; 
 polyethylene terephthalate (PET) with indium tin oxide (ITO); or 
 FR4. 
 
     
     
       11. The touch sensor of  claim 6 , wherein the plurality of drive and sense electrodes are formed on a first layer on the flexible substrate. 
     
     
       12. The touch sensor of  claim 11 , further comprising a coverlay disposed on top of the first layer. 
     
     
       13. The touch sensor of  claim 11 , further comprising a second layer disposed on an opposite side of the flexible substrate from the first layer, the second layer comprising a plurality of electrode connections. 
     
     
       14. A device comprising:
 a touch sensor comprising:
 a flexible substrate; 
 a plurality of sense electrodes and a plurality of drive electrodes disposed on the flexible substrate, wherein a portion of each of the plurality of sense electrodes is interleaved with a least a portion of one of the plurality of drive electrodes; and 
 a plurality of electrode branches, each particular electrode branch comprising a portion of at least one of the drive electrodes and a portion of at least one of the sense electrodes; and 
 
 one or more computer-readable non-transitory storage media embodying logic that is configured when executed to control the touch sensor; 
 wherein:
 the plurality of electrode branches comprises:
 a plurality of first electrode branches located on a first side of a central spine; and 
 a plurality of second electrode branches located on a second side of the central spine that is opposite to the first side; 
 
 when the touch sensor is not formed into a three-dimensional shape, at least a portion of one of the electrode branches is separated from an adjacent electrode branch by a gap; and 
 when the touch sensor is formed into the three-dimensional shape, the gap is substantially eliminated, thereby forming a substantially continuous touch-sensitive surface. 
 
 
     
     
       15. The device of  claim 14 , wherein the central spine comprises a plurality of tracks coupled to the plurality of sense and drive electrodes. 
     
     
       16. The device of  claim 15 , the touch sensor further comprising a connector coupled to the tracks of the central spine. 
     
     
       17. The device of  claim 14 , wherein:
 the plurality of sense electrodes and the plurality of drive electrodes comprise electrode teeth; and 
 electrode teeth of the sense electrodes are interdigitated with electrode teeth of the drive electrodes. 
 
     
     
       18. The device of  claim 14 , wherein the plurality of drive and sense electrodes are formed on a first layer on the flexible substrate. 
     
     
       19. The device of  claim 18 , the touch sensor further comprising a coverlay disposed on top of the first layer. 
     
     
       20. The device of  claim 18 , the touch sensor further comprising a second layer disposed on an opposite side of the flexible substrate from the first layer, the second layer comprising a plurality of electrode connections.